A plurality of semiconductor integrated circuits are tested simultaneously by the use of a tester in order to reduce costs and test time.
The tester includes a pin electronics section for transmitting a signal to and receiving a signal from a device under test (hereinafter abbreviated as a “DUT”). The number of DUTs simultaneously tested depends on the number of channels of the pin electronics section and the number of signal terminals of each DUT. The number of DUTs simultaneously tested is given by (number of channels of pin electronics section)/number of signal terminals of each DUT).
As can be seen from the above relationship, the number of DUTs simultaneously tested decreases as the number of signal terminals of a semiconductor integrated circuit used as each DUT increases. In addition, if the number of channels of the tester is small, the number of DUTs simultaneously tested is small. A decrease in the number of DUTs simultaneously tested leads to lower test throughput, longer test time, higher test costs, and the like.
Accordingly, for example, the number of testers is increased or the number of channels of a pin electronics section included in a tester is increased. However, such a technique requires that an installation area should be ensured, or leads to higher costs.
Therefore, the following technique has traditionally been used. An intermediate board is placed between a tester and a plurality of DUTs. A signal from the tester is inputted to input terminals of the plurality of DUTs by the use of the intermediate board. By doing so, the number of DUTs simultaneously tested can be increased.
By the way, recent semiconductor integrated circuits, such as SoC (System on Chip) devices, use various interfaces with a plurality of devices. In many cases, an input-output terminal (also referred to as a “bus terminal”) which is a two-way interface is used.
Japanese Laid-open Patent Publication No. 2004-361111
However, the use of an input-output terminal requires that switching between an input signal and an output signal should be performed. Accordingly, it is necessary, for example, to use an input signal line and an output signal line between a tester and an intermediate board. As a result, channels of the tester are used for this purpose and it is difficult to increase the number of DUTs simultaneously tested.